BUG: Non-Indexed Joins May Skip the Optimizer's Reformatting Step
Article ID: 172700
Article Last Modified on 10/3/2003
APPLIES TO
- Microsoft SQL Server 6.5 Standard Edition
This article was previously published under Q172700
BUG #: 16494 (6.5)
17158 (6.5)
SYMPTOMS
You may experience impaired performance when you process queries involving
joins on tables with no defined indexes. This problem has been identified
on SQL Server 6.5 only with Service Pack 2 and Service Pack 3 (and
intermediate builds between them). In one scenario, a query involving a non-
indexed join took approximately 840 minutes to execute on SQL Server 6.5
Service Pack 2, but only one minute on the release version of SQL Server
6.5. You may experience the degraded performance whether you use an ad-hoc
query or execute it within a stored procedure.
CAUSE
The Optimizer skips the Reformatting step for large tables with no indexes
defined. Earlier versions of SQL Server benefit significantly with the
Reformatting step included.
WORKAROUND
To work around this problem, define indexes on the tables.
STATUS
Microsoft has confirmed this to be a problem in Microsoft SQL Server
version 6.5. We are researching this problem and will post new information
here in the Microsoft Knowledge Base as it becomes available.
Additional query words: golden sp sp2 sp3
Keywords: kbbug kbusage KB172700